Private branch exchanges, or PBXs, are well-known in the art of telecommunications. Corporations, organizations, and other enterprises typically use PBXs to provide internal telephone services to their personnel. The personnel may call one another without using an external switched public telephone network, although the PBX is coupled to the public telephone networks for making external local and long distance calls. Telephones are usually coupled to the PBX by wireline connections. PBXs also typically implement a variety of features, including call waiting, call forwarding, conferencing, and call blocking.
Packet-switched computer networks are also common. Corporations and other enterprises typically use the computer networks to provide computer and data services to their personnel. The networks often take the form of a Local Area Network (LAN), a Wide Area Network (WAN), or a Metropolitan Area Network (MAN). These networks typically are used to transfer and share data files and to send and receive e-mail. In addition, developments in the area of Voice over IP (VoIP) allow the packet-switched networks to transmit voice messages.
Recently, interest in wireless networks has increased. Wireless networks allow mobile stations, or wireless units, to communicate over a wireless interface. The mobile station may be a wireless telephone communicating with a voice network over the wireless interface. The mobile station may also be a computer communicating with a data network over the wireless interface. Wireless communications may be over private or public networks. Operators of the wireless networks often wish to integrate the wireless networks into the existing PBXs and computer networks.
The PBX, wireless network, and computer network are usually separate networks since each of them often uses different protocols to transfer messages and manage elements of the network. The inability to fully integrate the wireless network with the PBX and computer network inhibits the wireless network from performing several key functions. Without full integration, mobile station users may have difficulty accessing the PBX and the computer network. Also, the mobile station users may not be able to roam between the private wireless network and the public wireless network. The mobile station user cannot move in and out of the private wireless network while talking. Instead, the user has to terminate the call, move to the other network, and reestablish a connection. In addition, the inability to fully integrate the networks may force the mobile station users to have two different wireless phones, one for the private wireless network and one for the public wireless network. Further, to provide PBX features in a wireless network, the wireless network operator typically installs substantial hardware and/or software in the wireless network to provide these features. However, even though the PBX-like features are implemented in the wireless network, the PBX and the wireless network still remain separate.